Yesterday's beautifully insane Futurama saw the characters swap bodies and lose all their inhibitions. The Professor joined the circus as Bender, Amy gorged multiple people to obesity, and Fry and Leela finally had sex...but in the wrongest bodies imaginable.

This was the second straight episode that felt like a return to old school Futurama storytelling. To some extent, it recalled the brilliant fourth season episode "The Farnsworth Parabox", which unleashed similar levels of craziness as the crew met alternate versions of themselves. But that episode feels downright pedestrian compared to "The Prisoner of Benda", because this one has sex. Horrific, horrific sex.

Amy and the Professor finish work on their latest invention, a machine that can switch people's minds (and, for the sake of narrative convenience/audience sanity, voices as well) from one body to another. Realizing each wants something that the other's body can provide - the Professor wants to be young and reckless, Amy wants to overeat with the Professor's emaciated body - they swap minds, but they soon discover the horrible catch - they can't switch the same minds back again.

While the Professor tries to figure out a mathematical theorem that will allow them to add enough extra minds to get back to their original bodies, Bender takes advantage of the situation (as is his eternal wont) by switching into Amy's body to steal the crown of the emperor of the Robo-Hungarian empire. The rest of the Planet Express crew also get into the craziness, as Leela takes on the Professor's body for a senior discount, while Fry puts his mind inside Doctor Zoidberg to prove to Leela that she's just as superficial about looks as she thinks he is. And that's where the depraved sex comes into play.

I'm only scratching the surface of what this episode is all about - I haven't even gotten to the Robo-Hungarian carnies, Bender's epic caper plans (which all hinged on the fact that he owns a watch), the robotic emperor's wish to be a common pauper, and the forbidden love between a janitor and his bucket. (More on that last one in a moment.) This episode is maybe the most epically overstuffed Futurama episode ever, with only the intersecting ensemble piece "Three Hundred Big Boys" even coming close. "The Prisoner of Benda" easily could have stretched out to a 70-minute DVD movie, but I'm just as happy to see it as 22 minutes of finely concentrated crazy.

Perhaps the most amazing part of this episode is that Leela and Fry finally consummated their love, and so much was going on that I almost missed the importance of it. Of course, when the two bodies that just had sex are Dr. Zoidberg and the Professor, it's kind of easy to miss the fact that a series milestone has just been reached. I suggested back in the recap for "The Late Philip J. Fry" that Fry and Leela can only really express their love for each other when faced with seemingly impossible obstacles - well, the circumstances of their first night of passion definitely qualify. Seriously, the logistics of it alone are simply mind-boggling.

Bender's storyline seemed almost sedate by comparison, but the epic climax at the United Nations was one of Futurama's all-time greatest scenes. It had it all - a self-sacrificing cannon, a chainsaw sword fight, tiny robotic clowns saving the day, a diplomat's arm getting chopped off, and Richard Nixon's jar getting smashed. (His head, sadly, survived.) Words really can't do that sequence justice.

Perhaps the episode's finest moment belonged to Scruffy. The slow-talking janitor was the only member of the Planet Express Crew to resist the infernal temptation of mind-switching, and he even managed to resist a far greater temptation: his favorite robotic wash bucket in Amy's body, ready to seduce him. Between Scruffy's plaintive command, "Go. Go now - before I beg you to stay" and his tough man tears...well, I never thought a Scruffy scene could qualify as heartbreaking. "The Prisoner of Benda" proved me wrong.

And then there was the math. At Comic Con, David X. Cohen mentioned this episode required writer Ken Keeler to come up with an entire theorem to explain how the minds could all get restored, with the final cavalcade of mind-switching a challenge to the viewer to figure out just how they did it. Well, here's my fairly straightforward chart of which minds were in which bodies in order, and I think they pulled it off. Of course, I'm just giving you the practical application. I leave it to you, the readers, to put the theory into proper mathematical notation.